Embryology of Exomphalos and Allied Malformations

Gastroschisis: embriology, pathogenesis, risk factors, prognosis, and ultrasonographic markers for adverse neonatal outcomes

Gastroschisis is the most common congenital defect of the abdominal wall, typically located to the right of the umbilical cord, through which the intestinal loops and viscera exit without being covered by the amniotic membrane. Despite the known risk factors for gastroschisis, there is no consensus on the cause of this malformation. Prenatal ultrasound is useful for diagnosis, prognostic prediction (ultrasonographic markers) and appropriate monitoring of fetal vitality. Survival rate of children with gastroschisis is more than 95% in developed countries; however, complex gastroschisis requires multiple neonatal interventions and is associated with adverse perinatal outcomes. In this article, we conducted a narrative review including embryology, pathogenesis, risk factors, and ultrasonographic markers for adverse neonatal outcomes in fetuses with gastroschisis. Prenatal risk stratification of gastroschisis helps to better counsel parents, predict complications, and prepare the multidisciplinary team to intervene appropriately and improve postnatal outcomes.

Anatomic parameters of omphaloceles and their association with anatomic, genetic, or syndromic malformations: a retrospective study

PURPOSE

This retrospective study aims to describe anatomical parameters of omphaloceles and to analyze their association with anatomical, genetic, or syndromic malformations.

METHODS

Cases were selected from digital records of two university centers, a certified regional registry and personal records. Patients from 1998 to 2018 with omphalocele and live birth (LB), termination of pregnancy due to fetal anomaly (TOPFA) and fetal death (FD) were included. Cases born outside Western Switzerland and/or with upper or lower coelosomy were excluded.

RESULTS

We analyzed 162 cases with the following distribution: 57 (35%) LB, 91 (56%) TOPFA and 14 (9%) FD. TOPFA was significantly more frequently performed in cases with non-isolated omphalocele, i.e., omphaloceles with associated major malformations (especially cardiovascular and genitourinary), genetic/chromosomal anomalies, or syndromes. For LB, associated anatomical malformations, genetic or chromosomal anomalies were not significantly associated with the size of the omphalocele or the liver involvement.

CONCLUSIONS

The proportion of cases resulting in TOPFA was higher among fetuses with major malformations, genetic or chromosomal anomalies. Despite the large size of this cohort, and in contrary to previous publications, the size of the omphalocele and/or liver involvement does not allow for conclusions regarding the presence or number of associated malformations, genetic or chromosomal anomalies.

Omphalocele and Cardiac Abnormalities-The Importance of the Association

Omphalocele is the most common ventral abdominal wall defect. Omphalocele is associated with other significant anomalies in up to 80% of cases, among which the cardiac ones are the most frequent. The aim of our paper is to highlight, through a review of the literature, the importance and frequency of association between the two malformations and what impact this association has on the management and evolution of patients with these pathologies. We reviewed the titles, the available abstracts, and the full texts of 244 papers from the last 23 years, from three medical databases, to extract data for our review. Due to the frequent association of the two malformations and the unfavorable effect of the major cardiac anomaly on the prognosis of the newborn, the electrocardiogram and echocardiography must be included in the first postnatal investigations. The timing of surgery for abdominal wall defect closure is mostly dictated by the cardiac defect severity, and usually the cardiac defect takes priority. After the cardiac defect is medically stabilized or surgically repaired, the omphalocele reduction and closure of the abdominal defect are performed in a more controlled setting, with improved outcomes. Compared to omphalocele patients without cardiac defects, children with this association are more likely to experience prolonged hospitalizations, neurologic, and cognitive impairments. Major cardiac abnormalities such as structural defects that require surgical treatment or result in developmental delay will significantly increase the death rate of patients with omphalocele. In conclusion, the prenatal diagnosis of omphalocele and early detection of other associated structural or chromosomal anomalies are of overwhelming importance, contributing to the establishment of antenatal and postnatal prognosis.

Anatomy and embryology of abdominal wall defects

Abdominal wall defects are one of the most frequently encountered human congenital anomalies. They are seen in as many as 1 in 2,000 live births with evidence to suggest that their incidence is increasing. While often discussed together abdominal wall defects consist mainly of two entities namely gastroschisis and omphalocele. There are marked differences in their theories of embryo-pathogenesis, clinical presentation/anatomy and overall outcomes. There is no clear consensus explaining the precise embryological mechanisms leading to the development of abdominal wall defects. Many clinicians and embryologists have attempted to explain the genesis of congenital abdominal wall defects because of failure of progression of various phases of normal embryonic development. This review summarizes the mechanisms involved in normal and abnormal development of the ventral abdominal wall leading to the development of gastroschisis and omphalocele.

Embryology of the Abdominal Wall and Associated Malformations—A Review

In humans, the incidence of congenital defects of the intraembryonic celom and its associated structures has increased over recent decades. Surgical treatment of abdominal and diaphragmatic malformations resulting in congenital hernia requires deep knowledge of ventral body closure and the separation of the primary body cavities during embryogenesis. The correct development of both structures requires the coordinated and fine-tuned synergy of different anlagen, including a set of molecules governing those processes. They have mainly been investigated in a range of vertebrate species (e.g., mouse, birds, and fish), but studies of embryogenesis in humans are rather rare because samples are seldom available. Therefore, we have to deal with a large body of conflicting data concerning the formation of the abdominal wall and the etiology of diaphragmatic defects. This review summarizes the current state of knowledge and focuses on the histological and molecular events leading to the establishment of the abdominal and thoracic cavities in several vertebrate species. In chronological order, we start with the onset of gastrulation, continue with the establishment of the three-dimensional body shape, and end with the partition of body cavities. We also discuss well-known human etiologies.

The complex search for the cause of gastroschisis

BACKGROUND

To reveal the complex etiology of gastroschisis through two independent cases.

CASES

Case 1 involves gastroschisis recurrence in a consanguineous marriage, and Case 2 concerns a fetus with gastroschisis whose mother had undergone gastroplasty. Methylation array was carried out in both cases (two fetuses with gastroschisis, their two mothers, one father from the consanguineous marriage), and in 16 controls (fetuses and their respective mothers).

CONCLUSION

The two cases presented different noninherited methylation profiles.

Exomphalos with intestinal fistulation: Case series and systematic review for clinical characterization, management and embryopathogenesis

INTRODUCTION

Exomphalos with intestinal fistulation (EIF) is a rare variant of exomphalos with intestine opening to the surface of an intact sac, and may result in a diagnostic challenge. We report 3 new cases and conducted a systematic review of the literature, to characterize its association with the type of exomphalos and vitellointestinal duct (VI) as well as to evaluate its management and outcomes.

METHODS

A literature search from PubMed using keywords pertaining to exomphalos and fistulation was used to identify all unique cases reported between 1950 and 2020, in addition to the case series reported here, to establish the clinical presentation, histological findings, management and outcomes.

RESULTS

We found a total of 28 cases of EIF, of which 25 had been reported in 70 years from 19 reports. There was a male predominance (4-to-1 ratio). The majority presented as an exomphalos minor (n = 23, 82%) with a prolapsing patent VI duct (n = 16, 57%), most had evidence of Meckel's diverticulum (n = 25, 89%). All but one case were managed by fistula excision with or without ileal resection and anastomosis, followed by primary closure of the abdominal wall defect. All patients, except one with Trisomy 13 who received only palliative care, underwent surgery. Post-operative complications occurred in 7 patients (25%). Congenital anomalies were present in 12 (43%) and none had Beckwith-Wiedemann syndrome. Mortality occurred in 4 patients (14%) between 3 and 17 days. One EIF with exomphalos major failed early conservative treatment due to sac disintegration and sepsis, requiring staged closure, but had a good outcome.

DISCUSSION

EIF is a rare entity usually associated with exomphalos minor and vitelline duct involvement. EIF presentation is variable but primary surgery is the mainstay of treatment with generally good outcomes. Common features of EIF suggest a different embryopathogenesis to other forms of exomphalos.

Ductus venosus reversed flow in omphalocele: Could it be a prognostic factor for long-term neurological impairment?

Omphalocele (exomphalos) represents one of the most frequent congenital abdominal wall defects. It presents as a defect of inconstant size and is located on the midline, at the base of the umbilical cord, the skin, fascia, and abdominal muscles being absent at this level. Omphaloceles are classified as liver-containing or non-liver-containing, the latter containing primarily bowel loops. We present the case of a 37-year-old pregnant woman with an early diagnosis of liver-containing omphalocele associating ductus venosus reversed flow, with the aim to highlight the importance of the first-trimester morphology scan and to develop a pilot study regarding the neurological development of infants after surgical repair of giant omphaloceles. The particularity of this case consists of a fetus with a positive diagnosis of a giant liver-containing omphalocele but with a small abdominal wall defect during the first-trimester morphology scan at 13 weeks and 3 days of gestation which associated ductus venosus reversed flow, presenting a normal karyotype postabortum. With a small defect, we can speculate the risk of strangling besides the mechanical traction exercised on the ductus venosus generating fetal distress, specifically fetal hypoxia at an early gestational age. In conclusion, the main issue, in this case, was if the fetal omphalocele and ductus venosus reversed flow indicated fetal hypoxia, what was the obstruction effect on the oxygenated blood pathway caused by the abdominal defect, and which were the long-term effects on infants with this complex pathology with an unknown outcome.

Embryonic developmental process and clinical anatomy of the preperitoneal fascia and its clinical significance

PURPOSE

Many researchers have different views on the origin and anatomy of the preperitoneal fascia. The purpose of this study is to review studies on the anatomy related to the preperitoneal fascia and to investigate the origin, structure, and clinical significance of the preperitoneal fascia in conjunction with previous anatomical findings of the genitourinary fascia, using the embryogenesis of the genitourinary system as a guide.

METHODS

Publications on the preperitoneal and genitourinary fascia are reviewed, with emphasis on the anatomy of the preperitoneal fascia and its relationship to the embryonic development of the genitourinary organs. We also describe previous anatomical studies of the genitourinary fascia in the inguinal region through the fixation of formalin-fixed cadavers.

RESULTS

Published literature on the origin, structure, and distribution of the preperitoneal fascia is sometimes inconsistent. However, studies on the urogenital fascia provide more than sufficient evidence that the formation of the preperitoneal fascia is closely related to the embryonic development of the urogenital fascia and its tegument. Combined with previous anatomical studies of the genitourinary fascia in the inguinal region of formalin-fixed cadavers showed that there is a complete fascial system. This fascial system moves from the retroperitoneum to the anterior peritoneum as the preperitoneal fascia.

CONCLUSIONS

We can assume that the preperitoneal fascia (PPF) is continuous with the retroperitoneal renal fascia, ureter and its accessory vessels, lymphatic vessels, peritoneum of the bladder, internal spermatic fascia, and other peritoneal and pelvic urogenital organ surfaces, which means that the urogenital fascia (UGF) is a complete fascial system, which migrates into PPF in the preperitoneal space and the internal spermatic fascia in the inguinal canal.

Exome sequencing of child-parent trios with bladder exstrophy: Findings in 26 children

Bladder exstrophy (BE) is a rare, lower ventral midline defect with the bladder and part of the urethra exposed. The etiology of BE is unknown but thought to be influenced by genetic variation with more recent studies suggesting a role for rare variants. As such, we conducted paired-end exome sequencing in 26 child/mother/father trios. Three children had rare (allele frequency ≤ 0.0001 in several public databases) inherited variants in TSPAN4, one with a loss-of-function variant and two with missense variants. Two children had loss-of-function variants in TUBE1. Four children had rare missense or nonsense variants (one per child) in WNT3, CRKL, MYH9, or LZTR1, genes previously associated with BE. We detected 17 de novo missense variants in 13 children and three de novo loss-of-function variants (AKR1C2, PRRX1, PPM1D) in three children (one per child). We also detected rare compound heterozygous loss-of-function variants in PLCH2 and CLEC4M and rare inherited missense or loss-of-function variants in additional genes applying autosomal recessive (three genes) and X-linked recessive inheritance models (13 genes). Variants in two genes identified may implicate disruption in cell migration (TUBE1) and adhesion (TSPAN4) processes, mechanisms proposed for BE, and provide additional evidence for rare variants in the development of this defect.

Midgut development in rat embryos using microcomputed tomography

The development of the mammalian gut was first described more than a century ago. Since then, it has been believed that a series of highly orchestrated developmental processes occur before the intestine achieves its final formation. The key steps include the formation of the umbilicus, the so-called "physiological herniation" of the midgut into the umbilical cord, an intestinal "rotation", and the "return of the gut" into the abdominal cavity. However, this sequence of events is predominantly based on histological sections of dissected embryos, a 2D technique with methodological limitations. For a better understanding of spatial relationships in the embryo, we utilized microcomputed tomography (µCT), a nondestructive 3D imaging method. Here, we show the detailed processes and mechanisms of intestinal development in rat embryos, including the development of the umbilicus, the formation of loops inside the umbilical coelom, and the subsequent shift of these loops into the abdominal cavity. Our 3D datasets of developing intestines will substantially advance the understanding of normal mammalian midgut embryology and offer new possibilities to reveal unknown mechanisms in the pathogenesis of congenital disorders.

Is fetal magnetic resonance imaging volumetry of eventrated organs in gastroschisis predictive for surgical treatment?

BACKGROUND

Fetal MRI is increasingly used in congenital abdominal wall defects. In gastroschisis, the role of fetal MRI in surgical therapy is poorly understood. Currently, the type of repair is determined primarily by clinical presentation and institutional preference.

OBJECTIVE

To evaluate the feasibility of fetal MRI volumetry in gastroschisis treatment.

MATERIALS AND METHODS

We included 22 cases of gastroschisis in this retrospective single-center study. Routine fetal MRI scans were acquired between Jan. 1, 2006, and July 1, 2018, at gestational ages of 19-34 postmenstrual weeks. Fetal-MRI-based manual segmentation and volumetry were performed utilizing steady-state free precision and T2-weighted sequences. Acquired parameters included intraabdominal volume, eventrated organ volume and total fetal body volume, and we calculated a volume ratio between eventrated organ volume and intraabdominal volume (E/I ratio).

RESULTS

Primary closure was conducted in 13 cases and silo bag treatment with delayed closure in 9 cases. Prenatal MRI volumetry showed a significantly higher E/I ratio in patients with silo bag treatment with delayed closure (mean [M]=0.34; 95% confidence interval [CI] 0.30, 0.40) than in primary closure (M=0.23, 95% CI 0.19, 0.27; P=0.004). We propose a volume ratio cutoff value of 0.27 for predicting silo bag treatment.

CONCLUSION

Fetal MRI predicted silo bag treatment in patients with gastroschisis in 90% of the cases in our cohort and might facilitate prenatal counseling and treatment planning.

Gastroschisis: A State-of-the-Art Review

Gastroschisis, the most common type of abdominal wall defect, has seen a steady increase in its prevalence over the past several decades. It is identified, both prenatally and postnatally, by the location of the defect, most often to the right of a normally-inserted umbilical cord. It disproportionately affects young mothers, and appears to be associated with environmental factors. However, the contribution of genetic factors to the overall risk remains unknown. While approximately 10% of infants with gastroschisis have intestinal atresia, extraintestinal anomalies are rare. Prenatal ultrasound scans are useful for early diagnosis and identification of features that predict a high likelihood of associated bowel atresia. The timing and mode of delivery for mothers with fetuses with gastroschisis have been somewhat controversial, but there is no convincing evidence to support routine preterm delivery or elective cesarean section in the absence of obstetric indications. Postnatal surgical management is dictated by the condition of the bowel and the abdominal domain. The surgical options include either primary reduction and closure or staged reduction with placement of a silo followed by delayed closure. The overall prognosis for infants with gastroschisis, in terms of both survival as well as long-term outcomes, is excellent. However, the management and outcomes of a subset of infants with complex gastroschisis, especially those who develop short bowel syndrome (SBS), remains challenging. Future research should be directed towards identification of epidemiological factors contributing to its rising incidence, improvement in the management of SBS, and obstetric/fetal interventions to minimize intestinal damage.

Body stalk anomaly presenting as an emergency in Ethiopia: a case report

BACKGROUND

Body stalk anomaly is a generally lethal malformation of the thorax and/or abdomen. It is often associated with limb defects. The intrathoracic and abdominal organs lie outside the abdominal cavity. These are contained within a sac composed of amnioperitoneal membrane attached directly to the placenta. The umbilical cord may be totally absent or extremely shortened. Severe kyphoscoliosis is often present. This case is reported to highlight this rare malformation and its clinical presentation.

CASE PRESENTATION

We present a case of a 27-year-old primigravida Oromo woman who had been amenorrheic for 9 months. She presented with an urge to bear down of 10 hours and passage of liquor of the same duration. The patient was referred from a district primary hospital with a diagnosis of preterm labor and hand prolapse. A lower uterine segment cesarean section was performed at Jimma University Medical Center for an indication of active first stage of labor with nonreassuring fetal heart rate pattern (fetal bradycardia) and hand prolapse to effect an anomalous fetus that had only a rudimentary right lower extremity and liver and intestine found outside the abdominal cavity contained within a sac composed of transparent membrane attached directly to the placenta. The umbilical cord was very short, measuring about 7 cm. The fetus had severe scoliosis. It also had a heartbeat upon extraction, which stopped after 5 minutes of delivery. The placenta and fetal body parts together weighed 2400 g.

CONCLUSION

Termination of pregnancy is usually offered because this abnormality is generally considered lethal. If the pregnancy is continued undetected as in our patient's case, vaginal delivery is recommended, given the highly lethal nature of this anomaly. Good prenatal screening and counseling are recommended for early detection and management.

Gastroschisis Is Associated With Placental Delayed Villous Maturation

Gastroschisis is a congenital abnormality characterized by visceral herniation through an abdominal wall defect. While the cause of gastroschisis is unknown, it has been linked to risk factors including young maternal age, smoking, and alcohol use during pregnancy. To date, the only established placental correlate is amniocyte vacuolization. Based on our clinical experience, we hypothesized that delayed villous maturation (DVM) is also associated with gastroschisis. We conducted a retrospective slide review of 23 placentas of neonates with gastroschisis. Additionally, we selected 2 control groups of placentas: 1 with a previous diagnosis of DVM and 1 with normal villous morphology. All placentas were randomized and reviewed by 2 perinatal pathologists, who were blinded to the group; DVM and amniocyte vacuolization were assessed. Gastroschisis was associated with increased placental DVM in 65.2% of cases (vs 13.6% of controls; P = .0007) and increased amniocyte vacuolization in 52.2% of cases (vs 9.1% of controls; P = .003) compared to the control group. Based on the normal and DVM groups, kappa agreement between current slide review and initial pathology diagnosis was 0.419, indicating moderate agreement. Our study shows that gastroschisis is associated with placental DVM. This association may be due to (1) a common upstream factor contributing to both gastroschisis and DVM or (2) DVM may be a consequence of the altered placental and amniotic environment in the context of gastroschisis.

Three-dimensional ultrasonographic features of diamniotic conjoined twins with body stalk anomaly

Background

Since conjoined twins were thought to be monoamniotic in the past, diamniotic conjoined twins would be improbable theoretically. Body stalk anomaly is a severe defect of the body wall, which is rare among twins. Body stalk anomaly in monochorionic diamniotic conjoined twins has never been reported prenatally so far as we know.

Case presentation

Here we present an extremely rare case of concordant body stalk anomaly in monochorionic diamniotic conjoined twins. Ultrasonography at 9 + 5 weeks revealed one chorionic and two amniotic cavities, close apposition of abdomen, limited movement, and common umbilical vessels. Follow-up ultrasonography at 11 + 6 weeks and 13 + 2 weeks showed close apposition of the lower abdominal region with cystic structures and a small bowel-like mass between the two fetuses. Three-dimensional ultrasonography assisted in observing the entire appearance of both twins in earlier first trimester, including amnioticity, conjoined region and umbilical vessels. We attribute this diamniotic conjoined twin in our case to the fusion theory. A single yolk sac was observed, challenging the idea that yolk sac number predicts amnionicity. Identification of single yolk sac and its allantois may form a common body stalk during this fusion, leading to concordant body stalk anomaly in monochorionic diamniotic twins.

Conclusions

Our case may provide important insights into both ultrasonographic features and embryogenesis of this extremely rare anomaly.

An Algorithmic Approach to Complex Fetal Abdominal Wall Defects

OBJECTIVE. The purpose of this article is to describe the imaging findings associated with complex fetal abdominal wall defects and provide an algorithmic method for arriving at a final diagnosis. CONCLUSION. Fetal ventral abdominal wall defects are a complex group of conditions with a broad spectrum of associated multisystem anomalies and manifestations. Correct characterization and classification of these defects require not only familiarity with imaging findings but also a systematic approach to avoid diagnostic confusion.

Bioinformatic Analysis of Gene Variants from Gastroschisis Recurrence Identifies Multiple Novel Pathogenetic Pathways: Implication for the Closure of the Ventral Body Wall

We investigated whether likely pathogenic variants co-segregating with gastroschisis through a family-based approach using bioinformatic analyses were implicated in body wall closure. Gene Ontology (GO)/Panther functional enrichment and protein-protein interaction analysis by String identified several biological networks of highly connected genes in UGT1A3, UGT1A4, UGT1A5, UGT1A6, UGT1A7, UGT1A8, UGT1A9, UGT1A10, AOX1, NOTCH1, HIST1H2BB, RPS3, THBS1, ADCY9, and FGFR4. SVS–PhoRank identified a dominant model in OR10G4 (also as heterozygous de novo), ITIH3, PLEKHG4B, SLC9A3, ITGA2, AOX1, and ALPP, including a recessive model in UGT1A7, UGT1A6, PER2, PTPRD, and UGT1A3. A heterozygous compound model was observed in CDYL, KDM5A, RASGRP1, MYBPC2, PDE4DIP, F5, OBSCN, and UGT1A. These genes were implicated in pathogenetic pathways involving the following GO related categories: xenobiotic, regulation of metabolic process, regulation of cell adhesion, regulation of gene expression, inflammatory response, regulation of vascular development, keratinization, left-right symmetry, epigenetic, ubiquitination, and regulation of protein synthesis. Multiple background modifiers interacting with disease-relevant pathways may regulate gastroschisis susceptibility. Based in our findings and considering the plausibility of the biological pattern of mechanisms and gene network modeling, we suggest that the gastroschisis developmental process may be the consequence of several well-orchestrated biological and molecular mechanisms which could be interacting with gastroschisis predispositions within the first ten weeks of development.

Mice doubly deficient in Six4 and Six5 show ventral body wall defects reproducing human omphalocele

Omphalocele is a human congenital anomaly in ventral body wall closure and may be caused by impaired formation of the primary abdominal wall (PAW) and/or defects in abdominal muscle development. Here, we report that mice doubly deficient in homeobox genes Six4 and Six5 showed the same ventral body wall closure defects as those seen in human omphalocele. SIX4 and SIX5 were localized in surface ectodermal cells and somatic mesoderm-derived mesenchymal and coelomic epithelial cells (CECs) in the PAW. Six4^-/-;Six5^-/- fetuses exhibited a large omphalocele with protrusion of both the liver and intestine, or a small omphalocele with protrusion of the intestine, with complete penetrance. The umbilical ring of Six4^-/-;Six5^-/- embryos was shifted anteriorly and its lateral size was larger than that of normal embryos at the E11.5 stage, before the onset of myoblast migration into the PAW. The proliferation rates of surface ectodermal cells in the left and right PAW and somatic mesoderm-derived cells in the right PAW were lower in Six4^-/-;Six5^-/- embryos than those of wild-type embryos at E10.5. The transition from CECs of the PAW to rounded mesothelial progenitor cells was impaired and the inner coelomic surface of the PAW was relatively smooth in Six4^-/-;Six5^-/- embryos at E11.25. Furthermore, Six4 overexpression in CECs of the PAW promoted ingression of CECs. Taken together, our results suggest that Six4 and Six5 are required for growth and morphological change of the PAW, and the impairment of these processes is linked to the abnormal positioning and expansion of the umbilical ring, which results in omphalocele.

Insights into the etiology and embryology of gastroschisis

The development of gastroschisis has long remained an area of interest and controversy. Successive theories about its pathogenesis are herein reviewed and discussed. Two historical assumptions, that omphalocele results from a persistent umbilical hernia, and that gastroschisis does not involve the umbilical cord, are dismissed. Therefore, one can envision gastroschisis for what it is, i.e. a ruptured physiological hernia. The causal agents for this intrauterine accident to occur are yet to be determined. Further bowel damage and complications can be explained by the mesenteric insult.

Understanding gastroschisis and its clinical management: where are we?

Gastroschisis is the commonest developmental defect of the anterior abdominal wall in both developed and developing countries. The past 30 years have seen transformational improvements in outcome due to advances in neonatal intensive care and enhanced integration between the disciplines of maternal fetal medicine, neonatology and pediatric surgery. A review of gastroschisis, which emphasizes its epidemiology, multidisciplinary care strategies and contemporary outcomes is timely. Areas covered: This review discusses the current state of knowledge related to prevalence and causation, and postulated embryopathologic mechanisms contributing to the development of gastroschisis. Using relevant, current literature with an emphasis on high level evidence where it exists, we review modern techniques of prenatal diagnosis, pre and postnatal risk stratification, preferred timing and method of delivery, options for abdominal wall closure, nutritional management, and short and long term clinical and neurodevelopmental follow-up. Expert commentary: This section explores controversies in contemporary management which contribute to practice and cost variation and discusses the benefits of novel nutritional therapies and care standardization that target unnecessary practice variation and improve overall cost-effectiveness of gastroschisis care. The commentary concludes with a review of fertile areas of gastroschisis research, which represent opportunities for knowledge synthesis and further outcome improvement.

Paradigm shift regarding the transversalis fascia, preperitoneal space, and Retzius' space

BACKGROUND

There has been confusion in the anatomical recognition when performing inguinal hernia operations in Japan. From now on, a paradigm shift from the concept of two-dimensional layer structure to the three-dimensional space recognition is necessary to promote an understanding of anatomy.

ANATOMY AND EMBRYOLOGY

Along with the formation of the abdominal wall, the extraperitoneal space is formed by the transversalis fascia and preperitoneal space. The transversalis fascia is a somatic vascular fascia originating from an arteriovenous fascia. It is a dense areolar tissue layer at the outermost of the extraperitoneal space that runs under the diaphragm and widely lines the body wall muscle. The umbilical funiculus is taken into the abdominal wall and transformed into the preperitoneal space that is a local three-dimensional cavity enveloping preperitoneal fasciae composed of the renal fascia, vesicohypogastric fascia, and testiculoeferential fascia. The Retzius' space is an artificial cavity formed at the boundary between the transversalis fascia and preperitoneal space. In the underlay mesh repair, the mesh expands in the range spanning across the Retzius' space and preperitoneal space.

Exposure to sub-lethal dose of a combination insecticide during early embryogenesis influences the normal patterning of mesoderm resulting in incomplete closure of ventral body wall of chicks of domestic hen

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Chlorpyrifos and cypermethrin treatment induced developmental anomalies in chicks.

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Protrusion of visceral organs and microphthalmia were the major anomalies observed.

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Treated embryos were conspicuous with incomplete ventral body wall and sternum.

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Altered expression pattern of E-cadherin, Shh, bmp4, Wnt11 and Pitx2 were recorded.

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Impairment of major regulators of development is suspected to induce VBWD.

Pesticide exposure to the non target groups especially during embryonic development has quite often resulted in congenital malformations. A commercially available combination insecticide (Ci, 50% chlorpyrifos and 5% cypermethrin) is known to induce ventral body wall defects (VBWDs) wherein abdominal viscera protrude out of the ventral body wall. Herein, an attempt was made to understand the mechanistic insight into Ci induced VBWDs. For this, before incubation, the chick embryos were dosed with the test chemical and then at different developmental stages of incubation, they were monitored for the changes in the expression of certain genes, which are indispensable for the ventral body wall closure since they regulate the cell fate, proliferation and survival. Concurrently, histopathological changes during the embryonic development were examined to corroborate the above observations. The results of mRNA profiling revealed a significant downregulation of Shh on day 4 and upregulation on day 10, while bmp4, Pitx2, E-cadherin, Wnt11, Wnt6, Pxn, MyoD1, Caspase-3, AHR, Cyp3A4, showed a significant upregulation on day 4 and/or on day 10. N-cadherin, fgf8, bmp1 showed no significant changes. The possible means by which these skewed expression patterns of regulatory molecules culminated into the VBWD are discussed.

The Upturned Superior Mesenteric Artery Sign for First-Trimester Detection of Congenital Diaphragmatic Hernia and Omphalocele

OBJECTIVES

The aim of this study was to follow the course of the superior mesenteric artery (SMA) in first-trimester fetuses to predict the location of the small bowel. Its abnormal course aids in early detection of congenital diaphragmatic hernia (CDH) and assessment of the contents of omphalocele.

METHODS

The SMA can be easily identified in a sagittal section of the fetus by using color Doppler sonography at the 11- to 14-week scan, and normally, it has a downward course caudally to supply the intestines. The course of the SMA points to the location of the bowel.

RESULTS

We report a series of 7 cases detected in first trimester with an abnormal course of the SMA, 3 of which had CDH and 4 of which had omphalocele. In CDH, the intestines herniate into the thoracic cavity; hence, the SMA tends to have an upward course toward the thorax. In 4 cases of omphalocele, the SMA follows the exteriorized bowel into the base of the umbilical cord.

CONCLUSIONS

Second-trimester sonography for detection of congenital malformations is a standardized protocol, but a careful anatomic survey at the 11- to 14-week scan is often rewarding. When there is a suspicion of an intrathoracic mass or a mediastinal shift, the upturned course of SMA serves as a valuable sign in confirmation of CDH. Chromosomal abnormalities are often reported in cases of omphalocele containing small bowel only, and the upward course of the SMA toward the base of the cord helps in its early prenatal diagnosis, which facilitates early genetic assessment in these fetuses.

Role of Ultrasound in Body Stalk Anomaly and Amniotic Band Syndrome

Body stalk anomaly (BSA) and amniotic band syndrome (ABS) are rare similar fetal sporadic polymalformative syndromes of unknown etiology, though there are certain differences between them. BSA is a combination of developmental abnormalities involving neural tube, body wall, and the limbs with persistent extra embryonic coelomic cavity. ABS is characterized by the presence of thin membrane-like strands attached to fetal body parts and causing constrictions and amputations. This is a cohort study involving 32,100 patients who were referred for routine antenatal ultrasound scan. The data was entered prospectively into a computer database. The duration of study was 3 years. In our study, ultrasound examination in 86 patients demonstrated ventral wall defects, craniofacial defects, and spinal and limb deformities as isolated or combined abnormalities. In those, 10 patients were suspected/diagnosed as BSA/ABS including a twin of a dichorionic diamniotic gestation. The typical features of body stalk anomaly can be detected by ultrasound by the end of the first trimester, which is important for the patient counselling and management. We are presenting these rare conditions and highlighting the importance of early sonographic imaging in diagnosing and differentiating them from other anterior abdominal wall defects.

Body Stalk Anomaly: Sonographic Pathologic Correlation

Body stalk anomaly is a severe defect and developmental abnormality that occurs in approximately one of 14,273 births. Sonographic examination of a 19-year-old woman, gravida 1, at approximately 22 weeks gestation, revealed a fetus with multiple coexisting congenital anomalies. This abnormality is uniformly fatal.

Management of gastroschisis

PURPOSE OF REVIEW

The diagnosis and treatment of gastroschisis spans the perinatal disciplines of maternal fetal medicine, neonatology, and pediatric surgery. Since gastroschisis is one of the commonest and costliest structural birth defects treated in neonatal ICUs, a comprehensive review of its epidemiology, prenatal diagnosis, postnatal treatment, and short and long-term outcomes is both timely and relevant.

RECENT FINDINGS

The incidence of gastroschisis has increased dramatically over the past 20 years, leading to a renewed interest in causation. The widespread availability of maternal screening and ultrasound results in very high rates of prenatal diagnosis, which enables evaluation of the optimal timing and mode of delivery. The preferred method of surgical closure continues to be an issue of debate among pediatric surgeons, whereas postsurgical treatment seeks to expedite the initiation and progression of enteral feeding and minimize complications. A small subset of babies with complex gastroschisis leading to intestinal failure benefit from the knowledge and expertise of dedicated interdisciplinary teams, which seek to bring novel therapies and improved clinical outcomes.

SUMMARY

The opportunities to increase the knowledge of causation, and identify best practices leading to improved outcomes, drive the ongoing need for collaborative clinical research in gastroschisis.

Gastroschisis and maternal intake of phytoestrogens

The prevalence of gastroschisis has increased significantly in the past few decades. The strongest risks have been observed for women <25 years old or of low body mass index, and maternal diet also been proposed to be associated with risk. The objective of this study was to evaluate whether the risk of gastroschisis is associated with maternal dietary intake of phytoestrogens. The analysis includes data on mothers of 409 gastroschisis cases and 3,007 controls who delivered their infants from 2005 to 2010 and participated in the National Birth Defects Prevention Study, a multistate, population-based, case-control study. Detailed information was obtained from maternal telephone interviews that included a validated food frequency questionnaire. We conducted logistic regression analyses that included each phytoestrogen in its continuous form (to test for linearity) and quadratic form (to test for non-linearity), adjusted for maternal energy intake, age, BMI, race-ethnicity, and smoking in 1st trimester. Logistic regression analysis indicated that biochanin A, formonoetin, and coumestrol had a significant non-linear association with gastroschisis (P-value <0.05 for quadratic term). Lower intakes were associated with increased risk, with somewhat stronger but relatively modest associations at the lower end of the distribution; for example, the ORs for the 10th versus 50th percentiles ranged from 1.1 to 1.2. Associations were not significant for the other phytoestrogens. This study provides some evidence for association with certain phytoestrogens, after adjusting for covariates. The implications of our findings for clinical practice are uncertain pending other studies examining this association. © 2016 Wiley Periodicals, Inc.

Multimodality Renal Failure in a Patient with OEIS Complex

Omphalocele-exstrophy of the bladder-imperforate anus-spinal defect (OEIS) complex is a rare constellation of clinical abnormalities with wide phenotypic presentation. We describe a case of a preterm neonate with OEIS complex with acute renal failure, and the challenges in diagnosis and management of this patient as renal failure can be a multifactorial process when encountered with this rare complex.

408 kb 15q11.2 microduplication by array comparative genomic hybridization in a fetus presenting with exomphalos, micrognathia, tetralogy of Fallot and normal karyotype: a genetic counseling dilemma in paternal carrier status

Exomphalos may be associated with chromosomal abnormalities and syndromes. Severe exomphalos (herniation of liver, midgut and spleen) associated with increased nuchal translucency was seen at first trimester screening test. Karyotype by chorionic villus sampling showed normal male fetus. Follow up scan at 16 and 18 weeks of gestation confirmed the severe exomphalos and detected micrognathia and tetralogy of Fallot. Array comparative genomic hybridization (a-CGH) further demonstrated a 408 kb 15q11.2 microduplication, with the father-to-be as healthy carrier. This is the first case of an association between 15q11.2 micorduplication and fetal sonographic anomalies. Genetic counseling for estimation of recurrent risk of congenital anomalies is discussed.

Interrupted inferior vena cava in fetuses with omphalocele. Case series of fetuses referred for fetal echocardiography and review of the literature

OBJECTIVES

Congenital heart disease is reported in 15-45% of omphalocele cases. Associated abnormalities of systemic veins have occasionally been reported in children and rarely documented in the fetus. We report a case series of interrupted inferior vena cava (Int-IVC) in association with omphalocele and review the literature.

METHODS

From our fetal database we identified all cases of omphalocele referred for fetal echocardiography (FE) between 1997 and 2012. We reviewed pre and postnatal medical records and performed a literature search from 1975 to present to identify previous relevant publications.

RESULTS

Of 9627 fetuses referred for FE, 34 had an omphalocele. Gestational age at FE was 17(+6) to 26(+4)weeks. Seven of the 34 fetuses were shown to have an Int-IVC with azygos continuation to a right-sided superior vena cava (SVC). The heart was structurally normal in all but one case. The abdominal wall defect was large and contained liver in all. There were three fetal demises and one neonatal death. Three cases were operated successfully. Since 1975, we identified 12 publications reporting omphalocele with systemic venous abnormalities. Abnormal IVC angulation may lead to surgical complications. Failure of IVC formation is likely to be a developmental rather than a situs abnormality. Int-IVC with a dilated azygos influences venous access and may predispose to venous thrombosis.

CONCLUSION

We have documented an association between large omphalocele and Int-IVC with azygos continuation to the SVC. In this small series, this did not have surgical implications. It will however, influence route of any future cardiac catheterisation and may have long-term implications.

Pulmonary complications of abdominal wall defects

The abdominal wall is an integral component of the chest wall. Defects in the ventral abdominal wall alter respiratory mechanics and can impair diaphragm function. Congenital abdominal wall defects also are associated with abnormalities in lung growth and development that lead to pulmonary hypoplasia, pulmonary hypertension, and alterations in thoracic cage formation. Although infants with ventral abdominal wall defects can experience life-threatening pulmonary complications, older children typically experience a more benign respiratory course. Studies of lung and chest wall function in older children and adolescents with congenital abdominal wall defects are few; such investigations could provide strategies for improved respiratory performance, avoidance of respiratory morbidity, and enhanced exercise ability for these children.

Prenatal MRI evaluation of limb-body wall complex

BACKGROUND

The sonographic (US) features of limb-body wall complex have been well documented; however the literature regarding the findings on MRI in limb-body wall complex is scant.

OBJECTIVE

To characterize the prenatal MRI features of limb-body wall complex.

MATERIALS AND METHODS

We performed a retrospective review of all MRI scans of fetuses diagnosed with limb-body wall complex at our institution from 2001 to 2011. Fetuses without correlating US scans or follow-up information were excluded. Three pediatric radiologists blinded to the specific US findings reviewed the prenatal MRIs. Images were evaluated for the organ location and attachment, the body part affected, characterization of the body wall defect, and spinal, limb and umbilical cord abnormalities.

RESULTS

Ten subjects met inclusion criteria. MRI was able to detect and characterize the body part affected and associated abnormalities. All fetuses had ventral wall defects, a small thorax and herniated liver and bowel. The kidneys were extracorporeal in three cases. The extruded organs were attached to the placenta or the uterine wall in all cases. Abnormal spinal curvatures of various degrees of severity were present in all cases. Eight cases had a short, uncoiled cord. Limb anomalies were present in 6 of the 10 cases.

CONCLUSION

We illustrate the common fetal MRI findings of limb-body wall complex. The prenatal diagnosis of limb-body wall complex and the differentiation of this defect from treatable abdominal wall defects are crucial to providing appropriate guidance for patient counseling and management.

Complex gastroschisis is a different entity to simple gastroschisis affecting morbidity and mortality-a systematic review and meta-analysis

BACKGROUND

Comparison of the outcome of newborns with simple (sGS) and complex gastroschisis (cGS: gastroschisis with atresia, necrosis, perforation or volvulus).

MATERIALS AND METHODS

We conducted a systematic database search, quality assessment and meta-analyzed relevant articles which evaluated the mortality and morbidity of newborns with cGS versus sGS. Risk ratios (RR) with 95% confidence interval (CI) were reported for categorical data, and the mean difference (MD) was calculated for continuous data. Pooled estimates of RR and MD were computed using generic inverse variance and a random-effects model.

RESULTS

Of 19 identified reports, 13 eligible studies were included. The mortality of infants with cGS (16.67%) was significantly higher than sGS (2.18%, RR: 5.39 [2.42, 12.01], p<0.0001). Significantly different outcome was found for the following parameters: Infants with cGS are started on enteral feedings later and they take longer to full enteral feedings with a subsequent longer duration of parenteral nutrition. Their risk of sepsis, short bowel syndrome and necrotizing enterocolitis is higher. They stay longer in hospital and are more likely to be sent home with enteral tube feedings and parenteral nutrition.

DISCUSSION

Occurring in 17% of infants born with gastroschisis, complex gastroschisis is associated with a significantly increased morbidity and mortality. More research should be focused on this special subgroup of patients, not only on postnatal management, but additionally directing efforts to improve diagnosing and predicting complex gastroschisis prenatally as well as implement any probable fetal intervention to alleviate its disastrous outcome.

Blastopathies and microcephaly in a Chornobyl impacted region of Ukraine

This population-based descriptive epidemiology study demonstrates that rates of conjoined twins, teratomas, neural tube defects, microcephaly, and microphthalmia in the Rivne province of Ukraine are among the highest in Europe. The province is 200 km distant from the Chornobyl site and its northern half, a region known as Polissia, is significantly polluted by ionizing radiation. The rates of neural tube defects, microcephaly and microphthalmia in Polissia are statistically significantly higher than in the rest of the province. A survey of at-birth head size showed that values were statistically smaller in males and females born in one Polissia county than among neonates born in the capital city. These observations provide clues for confirmatory and cause-effect prospective investigations. The strength of this study stems from a reliance on international standards prevalent in Europe and a decade-long population-based surveillance of congenital malformations in two distinct large populations. The limitations of this study, as those of other descriptive epidemiology investigations, is that identified cause-effect associations require further assessment by specific prospective investigations designed to address specific teratogenic factors.

A vascular and thrombotic model of gastroschisis

A binary vascular/thrombotic pathogenesis for gastroschisis, a form of congenital bowel herniation, is proposed, where normal right umbilical vein involution creates a possible site for thrombosis adjacent to the umbilical ring. If thrombosis occurs, it weakens the area, explaining overwhelmingly right-sided lesions. The model arises from the existence of two groups of risk factors with different maternal age associations. Older mothers show a greater association with vascular factors (although this may actually represent a lack of any significant maternal age effect), consistent with associations of gastroschisis with congenital heart lesions and with amyoplasia. Alternatively, other predispositions, and especially decreased maternal age, the greatest known risk factor, associate with factors raising maternal estrogen, with evidence that estrogen in turn acts here as a predisposition to thrombosis. Absorption of thrombotic by-products from the amniotic fluid can explain the unusual amniocyte inclusions that are common with gastroschisis, while a role for estrogens suggests a connection between rising gastroschisis prevalence and increasing environmental contamination with estrogen disruptors. This model explains a variety of structural and epidemiological findings, and suggests that stratification of data based on binary effects may clarify associated risks and mechanisms. The model also shows that what is often referred to as vascular disruption may actually reflect alternative or additional factors instead, including thrombosis as a primary mechanism.

Detection of structural abnormalities in the first trimester using ultrasound

During the past 25 years, embryonic and early fetal ultrasound and diagnosis have increasingly gained attention in pregnancy care. Modern high-frequency ultrasound transducers make it possible to obtain detailed images of the early conceptus and its organs, and thus move part of the anatomy and anomaly scan from the second to the first trimester. Today, detection of embryonic and fetal structural abnormalities in the first trimester has frequently been reported. One has to distinguish between diagnosis during the early period until about 10 weeks when the embryo or early fetus is small and transvaginal ultrasound is applied, and diagnosis during the late period at the nuchal translucency screening, usually carried out using transabdominal ultrasound. Early first-trimester abnormalities are often diagnosed by chance on clinical indications, whereas late first-trimester diagnoses are the result of systematic screening using ultrasound markers.

Thoracoabdominal wall defect with complete ectopia cordis and gastroschisis: a case report and review of the literature

Ventral wall defects are extremely rare anomalies that are likely caused by the failure of the ventral wall to close during week 4 of development. We report a case of severe thoracoabdominal wall defect including complete thoracic ectopia cordis and gastroschisis. This combination represents a novel constellation of findings in a single patient. This unique case further demonstrates an anatomically normal heart with age-appropriate development and an intact diaphragm. We review the literature of other reports and discussions of entities that share overlapping features with this case.